Who can give me a good ideas for a fantasy series?

I absolutely love the Harry Potter and Twilight series. I also like the Narnia series. Can someone please give me an idea of the first book to a fantasy series. This is not to read it is to write. I won't publish it this is purely for fun. Also, when I finish writing the story it will probably turn out differently than you though it would. I really want some ideas so please help.